Motor starting switch



July 5, 1949.

A. R. LUCAS MOTOR STARTING SWITCH Filed Jan. 24, 1947 A fro/:Ngys

Patented July 5, 1949 UNITED STATES PATENT OFFICE f MOTOR STARTING SWITCH Alfred R. Lucas, Galion, Ohio Application January 24, 1947, Serial No. 724,053

1 Claim.

The present invention relates to electric motor starting switches of the type wherein the starting winding is energized with the remaining winding and is later automatically disconnected.

Among the objects of the present invention is a switch of this type which will also act as a circuit breaker and re-make in case of overload.

Another object is a switch, including the circuit breaking feature, in which the reestablishment of the circuit after the break may be readily timed to control the length of the interval between such break and re-make.

Still other objects and advantages will be apparent to those skilled in the art upon reference to the following description and the accompanying drawings in which Figure 1 is a plan View of the switch showing the Wiring diagram.

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a section on line 3-3 of Figure 1.

Figure 4 is a section similar to Figure 2 but showing the parts in circuit breaking position.

In the drawings there is shown at Illa. a suitable insulating base having a stepped edge portion to receive an insulating cover member IOA. Fixed to the base I are three binding posts Il, i0, and 2l for the attachment of the three leads IIA, IGA, and 2IA, the latter being connected to one line from a suitable source of power. The lead IGA is connected through the running winding of the motor to the other power line. The lead I IA is connected through the starting winding to the said other power line. Fixed to binding post 2l inside of the housing I0-l0A is a conductor 22 leading to a somewhat elevated position upon a suitable spacer 22A where it is in direct contact with and holds rigidly a bi-metallie conducting loop member 23 having at its free end a contact 23A.

This contact 23A is adapted to make and break contact with another contact I2 carried on a conductor IIA leading from binding post Il. The conductor I IA will preferably be bent up to bring the contact I2 to just below the level of loop 23. Fixed to the loop 23 and extending back within the free end of the loop is a spring tongue 24. The free end of the tongue 24 constitutes one member of a toggle, the other member ci which is a small spring U-shaped piece 30 having laterally open notches one of which receives the end of tongue 24. The other notch in piece 30 receives and coacts with the edge of an insulating plate 30A held by the same screw, 22B, that holds conductor 22 and loop 23.

To the binding post I6 is fixed a conductor IBB bent upwardly an over the loop 23 to a position over the tongue 24 and carrying a contact I1 adapted under certain conditions to make contact with the tongues 24 while directly below the contact I1 a tongue stop I8 is fixed to the base I0.

In the operation of the switch, and assuming the motor idle, the several parts will be in the position of Figure 2, that is, both the circuits `will be closed. The contacts 23A and I2 will be together as will spring 24 and contact I1.

When the power lines are connected to the source, current will flow from conductor 22 through the loop 23 to lines IIA and IGA and to both windings. However, such current flow quick- 1y heats the bimetal loop which flexes and separates contacts 23A and I2, leaving contact I1 still closed with spring 24. This cuts down the flow through loop 23 and reduces the heating thereof sufficiently to stop the upward binding but enough heat will be generated to hold the contacts 23A and I2 separated.

If overloading or other excessive current demand occurs, the further heating of loop 23 Will cause further upward flexing. Under such conditions, toggle (spring 24 and member 30) acts to move the parts to the position of Figure 4 and thus also separate the contact I1 and spring 24 to stop the motor. When the current has been thus discontinued, the loop 23, of course, cools and flexes downwardly to restore the contact between II and the spring 24, and at the same instant restores contact between 23A and I2.

The time required for such cooling can be easily and accurately regulated by providing a variable resistance 40 in a circuit connecting the spring `stop IB with the lead 2IA.

I claim:

In a motor starting and safety switch a bilmetallic: flexible member adapted to be resistance heated and thereby flexed to break the starting circuit, said member adapted under excess current conditions to further flex and break the running circuit for said motor, and means for regulating the time of reestablishment of said running circuit due to cooling of said member, said regulating means consisting of a circuit shunted around said motor and containing a variable resistor, and means for establishing said shunt circuit upon breaking said running circuit.

ALFRED R. LUCAS.

REFERENCES CITED The following referenices are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,068,374 Carlson Jan. 19, 1937 2,095,579 Werner Oct. 12, 1937 2,117,123 Werner May 10, 1938 2,175,032 Schaefer Oct. 3, 1939 2,237,705 Kohl Apr. 8, 1941 2,280,960 Lee Apr. 28, 1942 2,304,018 Raney Dec. 1, 1942 2,379,602 Stickel July 3, 1945 

